Surgery Management of Recurrent Bilateral Drop Eye Syndrome in a Captive Silver Arowana (Osteoglossum Bicirrhosum) (Cuvier, 1829)

A silver arowana (Osteoglossum bicirrhosum Cuvier, 1829) with an estimated age of over 10 years old and measuring 81 cm total length was presented with bilateral drop eye syndrome while housed in a recirculating aquaculture system (RAS) at Aquaria KLCC. The condition was suspected to be associated with overfeeding and a high protein diet leading to excessive fat deposition around the eyes. The condition had been previously observed, and surgical correction was done in February 2025 through removal of dorsal orbital fat. The condition recurred after a month with prominence on the right side; thus, a second surgery was done on the 26th March 2025 which involved removing of the dorsal orbital fat and severing the ventral orbital tissue. The fish was anesthetized using isoeugenol via immersion and direct gill irrigation delivery method. Postoperatively, the fish was treated with dexamethasone as anti-inflammatory and vitamin C and B-complex to supplement the healing. The prognosis is considered good to fair following recovery.